Chainline/drivetrain issue and question. SOLVED!

[Clancy]

Ok, here's the deal.

I'm not going to mention the bike for now just in case. It's new and I'm starting to wonder if it's the problem.....

Dedicated gravel bike

SRAM Rival 22 hydro shifters with a Rival rear derailleur and a Force front derailleur. Everything is new except for the front derailleur, which is used but functions perfectly.

The crankset is the White Industries R30 sub compact 30/46, rear cassette is SRAM 11-32, less than 100 miles, new Shimano 11 speed chain. I just installed this crankset, prior I had a Force compact 34/50, but the problem described below happened with the Force crankset as well. Shim

I can get the shifting PERFECT using the small chainring but when I shift up to the big chainring, the shifting is off, acts as if there's not enough cable tension. If I tension the cable more to where it shifts correct, the shifting is off when I shift down to the small chainring plus now the guide pulls is no longer aligned perfectly under the small cog.

I have spent a HOURS trying to adjust, going crazy.

Derailleur hanger is perfectly aligned. I've checked it multiple times using the Park tool.

Cable is not dragging in the housing but to make sure I even ran a new cable.

So, if I'm doing everything correct when setting up the rear derailleur to shift properly in the small chainring- and let's assume I am doing it correctly-but the shifting is off when in the large chainring, what could it be?

Incorrect chainline?

The frame specs a 68 BSA BB and standard road crank. The rear spacing is 135.
The White Industries crank has a 45mm chainline if that helps with the diagnosis.

[Peter P.]

You sound like you know your technical stuff.

Have you tried measuring your chainline to verify it's actually 45mm?

Is the bare cable running through a plastic cable guide under the BB? Those guides usually have TWO mounting holes. Depending on which hole you mount it with, it will laterally shift the cable guide and can affect shifting.

[Clancy]

Originally Posted by Peter P.

You sound like you know your technical stuff.

Have you tried measuring your chainline to verify it's actually 45mm?

Is the bare cable running through a plastic cable guide under the BB? Those guides usually have TWO mounting holes. Depending on which hole you mount it with, it will laterally shift the cable guide and can affect shifting.

No, have not measured, but will, great idea.

No, continuous cable housing. Cable housing is run smoothly, no kinks/sharp bends. The shift cable, when disconnected from the derailleur, pulls and releases smoothly as I shift up and down. Derailleur functions fine and I've double checked my b limit screw multiple times.

I'm saying, I'm pulling my hair out, I can't figure it out.

[jtakeda]

I feel like the continuous housing is the issue.

What kind of housing?

[-dustin]

Acting up throughout entire range of cassette?

[Clancy]

Jagwire housing.

I can adjust the derailleur spot on, guide pully aligned with small cog, cable pull adjusted just slight of taunt, and it will shift perfectly up and down the full range, flawlessly, until I shift up into large chainring. Then shifting hesitates shifting up, drops down too fast, which is a symptom of not enough cable tension. I shift back down to small chainring, it shifts flawlessly.

[Satellite]

Do you have the derailleur cable in the right groove? Happened to me on a rear 7800 group. I tuned to bike to perfection and had to remove the rear derailleur cable for some reason. When I re-installed I put the cable on the wrong side of the fixing bolt. I couldn't get the bike to shift through out the whole range I could get the top and lower cogs spot on but the middle of the cassette was crap. I cried uncle and took the LBS they found the issue pretty quick and I was busy kicking myself. So they took pity and didn't even charge me for finding my error. I instead that I pay so I bought a case of beer and shared stories of dumb DIY customers.

Also check that your cassette lock ring is to the proper torque. Sounds simple but often over looked.

[-dustin]

Problem was evident with old crank...what about old cassette and chain?

Upright bike, right? Not a recumbent or something with an extra long wheelbase?

Med cage RD?

[cachagua]

If I'm doing everything correct when setting up the rear derailleur to shift properly in the small chainring- and let's assume I am doing it correctly-but the shifting is off when in the large chainring, what could it be?

Seems like the derailleur's out of plane somehow -- when it swings around to accommodate the big ring's taking up more chain, it sits farther outboard...? Bent mounting bolt? Cage bent? h'mm, you'd know if it were crossthreaded into the hanger. But is anything uneven where the back of the derailleur's end faces against the hanger that would lean it just the slightest bit?

Is the lower pivot -- in fact, are both pivots tight, with no play? What about the pulleys?

If you can somehow get hold of another derailleur to try, that might reveal something.

[commonguy001]

I'm in agreement with cachuga, really sounds like a rear derailleur issue.

I know you've checked the hanger alignment but picking up a second never hurts for a bike that gets banged around some and you could also try that just to see. I've gone through a couple on my Warbird between tranporting it and picking up debris on a trail so a spare if it's fine never hurts.

So I'd start with a second derailleur and a hanger which may just be a spare but still you'll have a spare if you don't need it.

[Clancy]

I just installed the sub compact crankset. Along with the crankset I installed a different cassette with closer ratios to take advantage of the sub compact.

Before that I had a standard compact crankset with an 11-36. I had the identical shifting problem.

before that, when I bought the frameset brand new I built it up as a 2x10 with Force shifters, Force compact crank, an X9 rear derailleur and the 11-36 cassette. I had the same shifting problem.

I agree it sounds like a bent hanger but I've always found a bent hanger will show up as shifting ok in the lower part of a cassette, than start skipping further up, or if adjusted to correct on the upper range, it will shift poorly on the lower cogs. A bent hanger does not shift perfectly in one chainring and poorly in another.

I currently have the bike adjusted perfect - it will shift flawless in the entire range of the 11-32 11T cassette up and down, both in the stand and when riding.

Shift to the big chainring, and it shifts poorly, as described.

So this pretty much eliminates the cable, housing, rear derailleur, shifter, or anything else I can think of as a problem.

This is why I'm really starting to question if the chainline is correct on the bike.

I've got an email into the manufacturer asking what the chainline is that they designed the bike around.

It's a standard 54 dedicated gravel road frame

I know there's some brilliant bike techs out there. What's the problem or what am I missing?

[weisan]

So this pretty much eliminates the cable, housing, rear derailleur, shifter, or anything else I can think of as a problem.

This is why I'm really starting to question if the chainline is correct on the bike.

Based on your conclusions, it's the bottom bracket then.

[stien]

A picture could be worth 1000 words in this case. Is the RD housing too short?

[-dustin]

always used a shimano chain?

i've had bikes with funky chainlines, but it never resulted in odd rear shifting.

[oldpotatoe]

Things I would check.

-Full der housing...no kinks, bends, smooth ends, ferrules? Might try 5mm housing and metal ferrules.

-Rear der cage alignment, pulley direction, cage not upside down.

-RH shifter..maybe something wonky inside?

-Chain length-maybe too short? Chain installed with 'shimano' facing outboard?